Pseudomembranous colitis is due to C. difficile infection, gram-positive bacillus that colonize the gut following transmission via the feco-oral route and disruption of the gut flora following course of antibiotic.
The organism produces 2 exotoxins: toxin A (enterotoxin) and toxin B (cytotoxin).
C. difficile May be detected in 1-3% of healthy adults and up to 50% of infants and children carry it.
Treatment of asymptomatic carriers is not recommended.
Pseudomembranous colitis occurs in only 10% of cases of antibiotic-associated diarrhea.
In 5-19%, it may be localized to the proximal colon.
Studies suggest that C. difficile and inflammatory bowel disease are being seen together more frequently. Rates have increased 2-fold for Crohn’s disease and 3-fold for ulcerative colitis.
When severe disease is encountered as manifested by pseudomembranes, colon wall thickening, WBC>15,000, creatinine rise by 50%, decreased albumin, and/or increased lactate treatment with vancomycin 125 mg qid for 7-14 days is recommended.
Recurrent C. difficile infection is thought to occur in 10-25% of patients. After one recurrence, additional recurrences are 40-60% more likely.
The organism produces 2 exotoxins: toxin A (enterotoxin) and toxin B (cytotoxin).
C. difficile May be detected in 1-3% of healthy adults and up to 50% of infants and children carry it.
Treatment of asymptomatic carriers is not recommended.
Pseudomembranous colitis occurs in only 10% of cases of antibiotic-associated diarrhea.
In 5-19%, it may be localized to the proximal colon.
Studies suggest that C. difficile and inflammatory bowel disease are being seen together more frequently. Rates have increased 2-fold for Crohn’s disease and 3-fold for ulcerative colitis.
When severe disease is encountered as manifested by pseudomembranes, colon wall thickening, WBC>15,000, creatinine rise by 50%, decreased albumin, and/or increased lactate treatment with vancomycin 125 mg qid for 7-14 days is recommended.
Recurrent C. difficile infection is thought to occur in 10-25% of patients. After one recurrence, additional recurrences are 40-60% more likely.
Which of the following is most commonly associated with the development of pseudomembranous colitis?
ReplyDelete1-Cefuroxime
2-Co-trimoxazole
3-Erythromycin
4-Flucloxacillin
5-Gentamicin
Clostridium difficile a Gram positive anaerobic bacterium is the cause of pseudomembranous colitis.
Studies show that when C. difficile colonise the gut they release two potent toxins, toxin A and toxin B, which bind to certain receptors in the lining of the colon and ultimately cause diarrhoea and inflammation of the large intestine or colon (colitis).
Commonly the disease is caused by broad spectrum antibiotics most commonly cephalosporins, broad spectrum penicillins, quinolones and clindamycin. Less commonly, macrolides, trimethoprim and sulphonamides have been reported to cause the disorder. Aminoglycosides, tetracyclines and chloramphenicol are rarely associated with psuedomembranous colitis.
Appropriate treatment includes metronidazole and oral vancomycin.
A 60-year-old man presents with a 5 day history of lower abdominal pain and diarrhoea. He has a history of chronic obstructive airways disease and has had numerous acute infective exacerbations over the last 3 months.
ReplyDeleteOn examination he was dehydrated, with a temperature of 38.6°C, a blood pressure of 102/72 mmHg and has a distended, tender abdomen. Which of the following is the most appropriate investigation for this patient?
1-Chest X-ray
2-Plain abdominal X-ray
3-Sigmoidoscopy and biopsy
4-Stool microscopy
5-Ultrasound scan of the abdomen
This is pseudomembranous colitis due to Clostridium Difficile secondary to antibiotic usage for his COAD. Plain AXR is useful for diagnosing toxic dilatation and would be the investigation of choice here due to his abdominal distension. Toxic dilatation should be excluded prior to sigmoidoscopy. However it does not establish the diagnosis. Stool microscopy has no value but stool toxin assay is useful. A patient with diarrhoea normally has involvement of the distal colon and rectum and sigmoidoscopy with biopsy is helpful for rapid diagnosis but should not be performed if toxic dilatation is suspected. Patients with involvement of right colon usually have little or no diarrhoea.
Pseudomembranous colitis occurs in only 3% to 5% of patients with C. difficile infection but is associated with a mortality rate of as high as 65%. Diarrhea may be minimal or absent because of ileus and may be present with abdominal pain or peritoneal signs. Vancomycin is often used as the first-line agent in critically ill patients. In the presence of ileus, vancomycin may be administered via a nasogastric tube with intermittent clamping of the tube.
ReplyDeleteThe gold standard diagnostic test to identify C. difficile toxin in the stool is a tissue culture cytotoxicity assay. The enzyme immunoassays are used widely for the detection of toxin A or toxins A and B of C. difficile in stool specimens. Although they have high specificity (75% to 100%) for toxins, the main drawback is that they are less sensitive than the cytotoxicity test (63% to 99%). Stool culture is sensitive (89% to 100%) but is not specific for toxin-producing strains to the bacterium. Sigmoidoscopic findings of colonic pseudomembranes are virtually pathognomonic for C. difficile colitis.
ReplyDeleteRisk factors for development of pseudomembranous enterocolitis in the absence of C. difficile includes intestinal surgery, intestinal ischemia, and other enteric infections. Pseudomembranous enterocolitis is associated with a wide variety of other intestinal disorders, and reports have included associations with Shigella infection, Crohn’s disease, neonatal necrotizing enterocolitis intestinal obstruction, Hirschsprung’s disease, and chronic carcinoma. Before the identification of C. difficile, the most common cause of pseudomembranous colitis was S. aureus infection, identified in stool cultures of patients with postoperative pseudomembranous enterocolitis.
ReplyDeleteQ: C. difficile diarrhea and colitis are caused by toxins, not by bacterial invasion of the colonic mucosa. Which of the following is false?
ReplyDelete1-C. difficile produces two structurally similar protein exotoxins, toxins A and B, which are the major known factors of these bacteria.
2-Toxin A is an inflammatory enterotoxin.
3-Toxin B is an extremely potent cytotoxin but has minimal enterotoxin activity in animals.
4-Toxin A is 10 times more potent than toxin B in causing injury and electrophysiologic changes in human colonic explants in vitro.
5-Toxin B is considered to be a major factor in the pathogenesis of C. difficile associated with diarrhea and colitis in humans.
4 correct
Toxin A is an inflammatory enterotoxin and toxin B is an extremely potent cytotoxin but has minimal enterotoxin activity in animals. Initial studies suggest that toxin B did not contribute to diarrhea and colitis in humans. It is known, however, that toxins A and B cause injury and electrophysiologic changes in human colonic explants in vitro and that toxin B is 10 times more potent than toxin A in inducing both of these changes.
C. difficile may be detected in 1-3% of healthy adults. Up to 50% of infants and children carry it. Treatment of asymptomatic carriers is not recommended. Pseudomembranous colitis occurs in only 10% of cases of antibiotic-associated diarrhea. In 5-19%, it may be localized to the proximal colon. Studies suggest that C. difficile and inflammatory bowel disease are being seen together more frequently. Rates have increased 2-fold for Crohn’s disease and 3-fold for ulcerative colitis. When severe disease is encountered as manifested by pseudomembranes, colon wall thickening, ascites, WBC>15,000, creatinine rise by 50%, decreased albumin, and/or increased lactate, treatment with vancomycin 125 mg qid for 7-14 days is recommended. Recurrent C. difficile infection is thought to occur in 10-25% of patients. After one recurrence, additional recurrences are 40-60% more likely.
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